Janthina globosa is a species of holoplanktonic sea snail, a marine gastropod mollusk in the family Epitoniidae, the violet snails or purple storm snails. Anatomy and Morphology Janthina globosa, commonly referred to as the violet snail, is a neustonic organism characterized by its thin, fragile purple shell and large size The maximum recorded shell length is 38.5 mm. Females normally grow to larger sizes than males, making it easy to distinguish between the sexes. Janthina globosa has a glossy shell, characterized by four symmetrical spirals evenly spaced on its shell. Inside its shell lives the organism itself. Protected by its hard outer shell, Janthina globosa has a soft body with forked cephalic tentacles on its belly, used for many different things like locomotion and receiving sensory input. Its unique purple color serves to camouflage itself in its environment and also serves as an efficient means of obtaining food, making it a better predator. It and many other members of the Janthina genera have an epipodium that is thought to help with balance in the water (Wilson and Wilson, 1956, 301). Feeding and Preferred Prey It secretes a purple dye (the same dye that gives it its purple color) to paralyze its prey, allowing it to eat its target without much of a fight. Although Janthina globosa seems like a harmless snail, it is an incredibly successful predator. Its most popular prey, based on scientific observation, seems to be Velella (Wilson and Wilson, 1956, 301) . Although scientists have observed that Velella is its favored prey option, upon gut analysis it seems that Janthina globosa will eat just about anything, even exhibiting cannibalistic behaviors by eating members of its own species. Velella has stinging nematocysts that they use to defend themselves and to capture prey. Janthina globosa are able to tolerate the poison excreted from Velella’s nematocysts, making them an easy target for predation by Janthina globosa. Unlike many other marine animals, Janthina globosa’s diet does not change too much as it matures. Janthina globosa seems to prefer larger Velella over smaller bodied Velella due to the availability of more soft tissue to eat as compared to the smaller members of that species. Since Velella is their preferred prey, Janthina globosa will appear in places it is not normally found if there is a large amount of Velella prey to consume. This makes the population size of Velella a good predictor